34 EasyLine EL3000 Series Commissioning InstructionsHousing PurgeHousing DesignRemark: Housing purge in the Fidas24 is described in a separate section,see below.Housing Purge is only possible with the wall-mount housing (EL3040model). The purging gas connectors (1/8-NPT female thread) are factory-installed based on orders.When does a housing purge become necessary?Housing purge becomes necessary when the sample gas containsflammable (see page 38), corrosive or toxic components.Purge GasThe following is to be used as purge gas: Nitrogen for measuring flammable gases and nitrogen or instrument air for measuring corrosive or toxic gases(Quality of instrument air in conformity with ISO 8573-1 Category 3,i.e. particle size max. 40 μm, oil content max. 1 mg/m 3, dew pointmax. +3 °C).NOTEFor Uras26, the purging gas must not contain any constituents of thesample components! Sample component constituents in the purging gascan falsify the measurement result.ATTENTIONLeaks may cause the purging gas to escape from the housing. Whenapplying nitrogen as purge gas, appropriate precautionary measuresmust be taken against asphyxiation!The purge gas flow must always be restricted upstream of the purgegas inlet! If the purge gas flow is not restricted until after the purge gasoutlet, the full pressure of the purge gas is exerted on the seals. Thiscan destroy the operator panel keypad!Initial Purging for Start-upPurging of the gas feed path: Purge gas flow max. 100 l/h,duration approx. 20 sPurging of the wall-mount housing: Purge gas flow max. 200 l/h,duration approx. 1 hIf the purge gas flow is lower than specified, the duration of the purgingmust be extended accordingly.
